An injection molding apparatus generally indicates an apparatus of manufacturing various plastic products (injection molding products) by injecting a thermoplastic resin which is a main raw material into an injection cylinder, melting the thermoplastic resin, pushing the melted resin into a cavity of a metal mold by a screw of a hydraulic plunger or an extruder, and then cooling and hardening the resin. The metal mold used in the injection molding as described above is called an injection mold.
In an injection molding apparatus disclosed in US Patent Laid-Open Publication No. 2001-0193266, a mold and a cavity which is a space into which a melted resin is inserted to manufacture an injection molding product are formed integrally with each other in the mold.
Therefore, in the injection molding apparatus according to the related art, the mold and the cavity are formed integrally with each other, such that a size of the cavity may not be adjusted.
Further, in the injection molding apparatus according to the related art, the mold and the cavity are manufactured integrally with each other so as to be matched to a thickness of a product inserted into the cavity, such that it is required to manufacture a plurality of molds so as to be matched to a thickness of an inserted injection molding product.
Further, in the injection molding apparatus according to the related art, when the thickness of the injection molding product is changed, the mold is replaced and again installed, such that manpower is wasted and production of an injection molding product is delayed.